"I think this is the most vulnerable transportation corridor in Canada right now to environmental issues," said Bill Casey, the Liberal MP for Cumberland-Colchester, who announced the study.

Casey said the federal government will provide $350,000 for the study and the provinces of New Brunswick and Nova Scotia will each contribute $175,000.

It's important to take action, Casey said.

"In 2015, the water came within one centimetre of the top of the rail line," Casey said. "The rail line is actually the coastline.

"It was never meant to be a breakwater or a dike but that's what it's doing now. The rail line, for a couple of kilometres, holds back the entire ocean and on the other side of the rail line is below sea level and that includes the Trans-Canada Highway, the pipeline, the power lines and so on.

"So the risk is high and the consequences are grave if it was to fail."

- Bay of Fundy dikes need to be repaired, says Sackville mayor

Sackville Mayor John Higham said he's pleased the study is going forward.

The town near the New Brunswick end of the isthmus is limited in what it can do, but the area has been a concern for years, he said.

"We don't own the dikes, we don't maintain them," Higham said, "It's outside of our jurisdiction, so we can't assist in protecting that national infrastructure."

Sackville, however, is in one of the places that could be severely affected "if things go wrong on the flooding," he said.

Higham said he'd like to see changes made to protect the isthmus, but getting it right is important.

"We want to go through it logically, which is what they're doing, which is 'Let's get some experts together to look at this,'" he said.

"This is quite an engineering challenge to build a significant water abatement facility on mud because the Tantramar Marsh is 40 to 60 feet of mud, which creates some really interesting engineering challenges."

He said the solution needs an interdisciplinary approach, with experts looking at habitat, flood protection, the environmental value of the area, and recreational possibilities.

"What we create is going to be a hugely important structure but also with getting people out there and using them and seeing them they'll understand the value of it," Higham said.

MP sees urgency

Casey said details of the study still need to be worked out, but he feels time is of the essence.

"There are 480,000 containers unloaded and loaded in Halifax every year — that's 1,300 a day, and most of them go across this rail line to Central Canada or the U.S.," he said.

"And the auto port in Halifax ships 230,000 cars across that rail line.

"If it was to be breached or shut down, the consequences would be — oh, they'd be dramatic."

Casey said the study will include an engineering assessment, consultation and options to protect the transportation route through the isthmus, which is 17 kilometres at its narrowest point and about 24 kilometres at its widest.

He said it is too early to outline solutions, but the rail line might have to be raised or reinforced.

"The problem is you can't interrupt that rail line without interrupting an enormous amount of business," Casey said. "There's $50 million a day that goes across that isthmus … by the Trans-Canada Highway and the rail line."